There was also no way for a normal person to easily and cheaply communicate with 20 million people in realtime.

If you're a normal person, you still can't, but it definitely looks like you can by ad-supported social networks. If you have 20 million followers on Facebook, your posts aren't guaranteed to reach them, unless you pay Facebook as an advertiser. Running a web server that handles and actually gets 20 million simultaneous connections for any length of time requires you to spend/have money or not be a normal person.